Signal detector

ABSTRACT

A method, apparatus, and system for detecting a tone.

BACKGROUND OF THE INVENTION

In certain computer networks including, for example, the Internet, nodescommunicate by way of modulated and demodulated asynchronous orsynchronous signals. Those signals may be transmitted and received by,for example, modems, narrow-band communications or broadbandcommunications such as Digital Subscriber Line (“DSL”) transceivers.Those transceivers may furthermore operate under one or more commonprotocols such as, for example, Transmission Control Protocol andInternet Protocol (“TCP/IP”). Transceivers communicating by way ofcommon protocols may exchange capabilities and select a common mode ofoperation. Such an exchange of capabilities and a selection of a commonmode of operation are sometimes performed by a so-called “handshake.”That handshake may be accomplished by way of a mechanism such asInternational Telecommunication Union Standard G.994.1 for DSLcommunication, for example.

After two communicating transceivers reach an agreement on a commonworking mode, transceivers may enter an activation phase. In the exampleof asymmetric digital subscriber line (“ADSL”) ( G.992.1, G.992.2,G.992.3 and G.992.4 standards, an activation phase may include channeldiscovery, training, channel analysis, and exchange. During thosepre-data mode phases, transceivers may diagnose the channelcharacteristics, train the systems, analyze the communication channel,and communicate a set of showtime or data mode capability parameters,respectively.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter regarded as embodiments of the invention isparticularly pointed out and. distinctly claimed in the concludingportion of the specification. Embodiments, however, both as toorganization and method of operation, together with objects, features,and advantages thereof, may best be understood by reference to thefollowing detailed description wherein like reference numerals areemployed to designate like parts or steps, when read with theaccompanying drawings in which:

FIG. 1 is a block diagram of a system suitable for practicing anembodiment of the invention;

FIG. 2 is a block diagram of a device suitable for practicing anembodiment of the invention;

FIG. 3 is a flowchart depicting a tone detection method suitable forpracticing an embodiment of the invention;

FIG. 4 a is a simulated signal plot for a 276 sample window sizesuitable for practicing an embodiment of the invention; and

FIG. 4 b is a simulated signal plot for a 256 sample window sizesuitable for practicing an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the preferred embodiments of thepresent tone detection invention, examples of which are illustrated inthe accompanying drawings. It is to be understood that the Figures anddescriptions of embodiments of the tone detection invention includedherein illustrate and describe elements that are of particularrelevance, while eliminating, for purposes of clarity, other elementsfound in typical computers and computer networks.

One example of tone use that may benefit by use of embodiments of thepresent tone detection techniques is to communicate information betweentelephony equipment in certain communication systems. In those telephonybased communication systems, tone detection may be implemented andemployed at both receivers and transmitters. A telephony card or a modemare two examples of devices that may be employed in such communicationsystems. When a receiver detects a tone, also known as a touch tone, thetone may be passed along to an application such as, for example, WindowsTelephony API™ and then to an active call center. Issues that arise inconnection with tone transmission include, for example, the tonedetection capabilities of the tone receiver are not robust enough todetect tones that are imperfect, the tone transmitter being used to dialthe active call center generates tones that are too short for the tonereceiver to detect, and the telephony being used to dial the Active CallCenter system generates touch tones that are imperfect or outside thebounds recognized by the tone receiver. Generation of tones that are tooshort for the tone receiver to detect is particularly common withdigital phone systems that generate “blips” instead of longer tones.

Embodiments of the tone detection invention may be applied to signalsother than tones. For example, the detection techniques provided hereinmay be utilized with REVERB, SEGUE, and MEDLEY signals. Embodiments ofthe tone detection techniques may also be applied to signals other thanthose used in the handshaking phase. For example, the channel discovery,training, channel analysis, and exchange phases may be appropriate forutilization of the tone detection techniques provided herein. Thosenon-handshaking phases may use COMB and ICOMB signals, all of which maybe compatible with embodiments of the tone detection techniques providedherein. Definitions for the COMB, ICOMB, REVERB, SEGUE and MEDLEYsignals may be found in the ITU standards G.992.3. Thus, there may be aneed for a simple, cost effective signal and tone detector. There mayalso be a need for a robust, stable tone detector.

The tone detection techniques described herein provide solutions to theshortcomings of certain communication systems. Those of ordinary skillin communication system technology will readily appreciate that the tonedetection techniques, while described in connection with DSLcommunication, are equally applicable to other communication systems.Other details, features, and advantages of the tone detection techniqueswill become further apparent in the following detailed description ofthe embodiments.

Any reference in the specification to “one embodiment,” “a certainembodiment,” or a similar reference to an embodiment is intended toindicate that a particular feature, structure, or characteristicdescribed in connection with the embodiment is included in at least oneembodiment of the invention. The appearances of such terms in variousplaces in the specification are not necessarily all referring to thesame embodiment. References to “or” are furthermore intended asinclusive so “or” may indicate one or the other ored terms or more thanone ored term.

The Internet is a network of nodes such as computers, dumb terminals, orother typically processor-based, devices interconnected by one or moreforms of communication media. Typical interconnected devices range fromhandheld computers and notebook PCs to high-end mainframe andsupercomputers. The communication media coupling those devices includetwisted pair, co-axial cable, optical fibers and wireless communicationtechniques such as use of radio frequency.

A node is any device coupled to the network including, for example,routers, switches, servers, and clients. Nodes may be equipped withhardware, software or firmware used to communicate information over thenetwork in accordance with one or more protocols. A protocol maycomprise a set of instructions by which the information signals arecommunicated over a communications medium. Protocols are, furthermore,often layered over one another to form something called a “protocolstack.”

In one embodiment, for example, the network nodes operate in accordancewith a seven layer Open-Systems Interconnect (“OSI”) architecture. TheOSI architecture includes (1) a physical layer, (2) a data link layer,(3) a network layer, (4) a transport layer, (5) a session layer, (6) apresentation layer, and (7) an application layer. The physical layer isconcerned with electrical and mechanical connections to the network andmay, for example, be performed by a token ring or bus. The data linklayer arranges data into frames to be sent on the physical layer and mayreceive frames. The data link layer may receive acknowledgement frames,perform error checking and re-transmit frames not correctly received.

The network layer determines routing of packets of data and may beperformed by, for example, Internet Protocol (IP) as defined by IETFstandard 5, RFC 791 (IP Specification), adopted in September, 1981 andavailable from www.ietf.org. The transport layer establishes anddissolves connections between nodes. The transport layer function iscommonly performed by a packet switching protocol referred to as theTransmission Control Protocol (TCP). TCP is defined by the Internetengineering Task Force (IETF) standard 7, Request for Comment (RFC) 793,adopted in September, 1981 (TCP Specification). The network andtransport layers are often referred to collectively as “TCP/IP.”

The session layer establishes a connection between processes ondifferent nodes and handles security and creation of the session. Thepresentation layer performs functions such as data compression andformat conversion to facilitate systems operating in different nodes.The application layer is concerned with a user view of network data, forexample, formatting electronic messages.

Nodes may operate as source nodes, destination nodes, intermediate nodesor a combination of those source nodes, destination nodes, andintermediate nodes. Information is passed from source nodes todestination nodes, often through one or more intermediate nodes.Information may comprise any data capable of being represented as asignal, such as an electrical signal, optical signal, acoustical signaland so forth. Examples of information in this context may include datato be utilized by the node in which the data resides, data to betransferred to another node and utilized therein, and so forth.

Embodiments of the tone detection invention may be applied to nodescommunicating by way of communications mediums such as, for example,modems, voice-band, or broadband communication mediums. Certain examplesprovided herein describe embodiments wherein nodes communicate by way ofDSL as an example. In communications, the term “baud” is used torepresent unique line conditions. Each unique line condition is referredto as a symbol. In certain systems, one bit is sent in conjunction witheach symbol, while in other systems multiple bits are sent inconjunction with each symbol. For example, Quadrature AmplitudeModulation (“QAM”) may utilize phase shifts and amplitude to permit thetransmission of a number of bits per symbol. A plurality of samples aretransmitted and received to create or read a signal that represents eachsymbol. Embodiments of the present invention may be applied to eithersingle or multiple bit transmissions per symbol. Bit transmission istypically expressed in bps, or bits per second.

Communication over a communication media may be performed synchronouslyor asynchronously. In asynchronous and synchronous communicationsystems, tones and other signals are often used to communicateinformation between transmitting and receiving nodes. That informationmight include state information regarding changes of state from onesignal state to another signal state. For example, a state of atone-signal may change a state of REVERB-signal state and vice versa.

Various compatibility issues exist within standards such as ADSL.Therefore, prior to commencement of the data mode, one or morehandshaking or other preliminary modes may be performed to assure thattransmitting and receiving nodes are compatible, for example, regardingspectrum compatibility and speed of communication. Embodiments of thetone detection techniques may be particularly useful during pre-datamode operation to efficiently synchronize transmitting and receivingnodes.

A synchronizing device may include an analog front end (“AFE”) that maybe used to transmit data across an analog medium, may receive such data,and may be used for clock correction. The AFE may include an analogfront end clock (“AFE clock”). The AFE may also include a digital toanalog converter (“DAC”) and a transmit circuit for converting digitaldata and transmitting that data across an analog medium to another node.The AFE may furthermore include an analog to digital converter (“ADC”)and a receive circuit for receiving and converting data from anothernode.

In an embodiment of the present synchronization device, an AFE mayprovide a sampling frequency of 4.416 MHz plus or minus a maximumpermissible error. Those errors may furthermore be expressed in units ofparts per million (“ppm”). The maximum permissible error for the AFE maybe required to be within 50 ppm.

A digital signal processing device (“DSP”) may also be utilized in tonedetection. A DSP typically includes a math processor so that it mayquickly perform complex operations on a signal representing a digitalstream of information that is being transmitted or received. DSPs mayalso often be programmed to, for example, adjust a sampling rate of thesignal.

FIG. 1 illustrates a tone detection system 100 in which embodiments ofthe present invention may be implemented. Node 1 101 may be a networkserver. Node 2 102, node 3 103, and node 4 104 may be general-purposecomputers or client processors. Node 5 105, node 6 106, and node 7 107may be network routers or switches. Any of those nodes 101-107 mayinclude an implementation of an embodiment of the tone detectiontechniques. The nodes 101-107 illustrated in FIG. 1 are coupled to anetwork 108 and may communicate therewith. Internodal communication maybe achieved utilizing DSL or another communication medium.

FIG. 2 illustrates a tone detection device 112 in an embodiment in whichtone detection is performed at a node. That tone detection device 112includes memory 114, a processor 122, a storage device 124, an outputdevice 126, an input device 128, a communication adaptor 130, an analogfront end 136 and a digital signal processor 146. Communication betweenthe processor 122, the storage device 124, the output device 126, theinput device 128, and the communication adaptor 130 may be accomplishedby way of one or more communication busses 132. It should be recognizedthat the tone detection device 112 may have fewer components or morecomponents than shown in FIG. 2. For example, if a user interface is notdesired, the input device 128 or output device 126 may not be includedwith the tone detection device 112.

The memory 114 may, for example, include random access memory (RAM),dynamic RAM, and/or read only memory (ROM) (e.g., programmable ROM,erasable programmable ROM, or electronically erasable programmable ROM)and may store computer program instructions and information. The memory114 may furthermore be partitioned into sections in which operatingsystem 120 instructions are stored, a data partition 118 in which datais stored, and a tone detection module 116 partition in whichinstructions for tone detection may be stored. The tone detection module116 partition may also allow execution by the processor 122 of theprogram instructions to detect tones communicated between one or morenodes 101-107. The data partition 118 may furthermore store data to beused during the execution of the program instructions such as, forexample, tone processing calculations.

The processor 122 may, for example, be an Intel® Pentium® type processoror another processor manufactured by, for example Motorola®, Compaq®,AMD®, or Sun Microsystems®. The processor 122 may furthermore executethe program instructions and process the data stored in the memory 114.In one embodiment, the instructions are stored in memory 114 in acompressed and/or encrypted format. As used herein the phrase, “executedby a processor” is intended to encompass instructions stored in acompressed and/or encrypted format, as well as instructions that may becompiled or installed by an installer before being executed by theprocessor.

The storage device 124 may, for example, be a magnetic disk (e.g.,floppy disk and hard drive), optical disk (e.g., CD-ROM) or any otherdevice or signal that can store digital information. The communicationadaptor 130 may permit communication between the tone detection device112 and other devices or nodes coupled to the communication adaptor 130at the communication adaptor port 134. The communication adaptor 130 maybe a DSL or other type of network interface that transfers informationfrom nodes on a network to the tone detection device 112 or from thetone detection device 112 to nodes on the network. The network may be alocal or wide area network, such as, for example, the Internet, theWorld Wide Web, or the tone detection system 100 illustrated in FIG. 1.It will be recognized that the tone detection device 112 may alternatelyor in addition be coupled directly to one or more other devices throughone or more input/output adaptors (not shown).

The tone detection device 112 may also be coupled to one or more outputdevices 126 such as, for example, a monitor or printer, and one or moreinput devices 128 such as, for example, a keyboard or mouse. It will berecognized, however, that the tone detection device 112 does notnecessarily need to have an input device 128 or an output device 126 tooperate. Moreover, the storage device 124 may also not be necessary foroperation of the tone detection device 112.

The analog front end 136 may include a clock 138, a receive circuit 140,a transmit circuit 142, and a synchronization circuit 144. The digitalsignal processor 146 may receive samples from the AFE and include aFourier transform module and a tone detector.

The elements 114, 122, 124, 126, 128, and 130 of the tone detectiondevice 112 may communicate by way of one or more communication busses132. Those busses 132 may include, for example, a system bus, aperipheral component interface bus, and an industry standardarchitecture bus.

The present tone detection techniques provide reliable, robust, costeffective tone detection. Reliable tone detection results from theability of the techniques to minimize loss of signal. Robust tonedetection results from the ability of the techniques to detect tones ata fast rate. Cost effective tone detection results from the ability ofthe tone detection techniques to reduce design costs. The present tonedetection techniques provide those benefits both in relation to singletone and multi-tone detection. The techniques can also be used for othersignal detections.

Embodiments of the tone detection invention utilize a number of samplesreceived or transmitted per signal that minimizes sample processing loadwhile maximizing the reliability and robustness of tone detection.

In an embodiment of the present signal detection invention, a method ofsignal detection is provided. That method includes communicating thesignal by applying a first quantity of samples per period, communicatingthe signal by applying a second quantity of samples per period, andtranslating the samples into communicated signal information. The signalmay include a representation of one or more tones that in turn representinformation. The period may be the time required to communicate asymbol.

Translating the samples may include translating the first quantity ofsamples into information carried on the signal, translating the secondquantity of samples into information carried on the signal, andidentifying information translated from one of the first quantity ofsignals, the second quantity of signals, and the first and secondquantities of signals. Those quantities of signals may, furthermore, bepredetermined by, for example, experimentation.

That embodiment is able to detect multiple tones to determine a commoncommunication capability. Thus, communication may be commenced utilizinga mode that is common to each node such as, for example, the A4, A43,B43, and C43 carriers.

Signal processing devices are also contemplated. A transmitting deviceincludes a signal transmitting circuit and a digital signal processordetecting a tone utilizing a sample block of a first window size andutilizing a sample block of a second window size. A receiving deviceincludes a signal receiving circuit and a digital signal processordetecting a tone utilizing a sample block of a first window size andutilizing a sample block of a second window size. The signal receivingand transmitting circuits may include analog front ends.

An article of manufacture is also contemplated. That article ofmanufacture includes a computer readable medium having stored thereoninstructions. When executed by a processor, those instructions cause theprocessor to communicate a signal by applying a first quantity ofsamples of the signal per period, communicate the signal by applying asecond quantity of samples of the signal per period, and translate thesamples into communication information.

FIG. 3 illustrates a method of tone detection 200 that detects one ormore tones carried in one or more signals. The method includes receivingraw samples at 202, processing an appropriate number of samples perperiod at 204 and 206, processing those samples utilizing a Fouriertransform at 208, and detecting one or more tones present in the signalcarrying the block of samples at 210. The period may, for example, bethe period during which a symbol is transmitted or received. The Fouriertransform may furthermore be, for example, a discrete Fourier transform(“DFT”) or fast Fourier transform (“FFT”),

Embodiments of tone detection systems, apparatuses, and methods will bedescribed in connection with the ITU G.994.1 standard. It should berecognized that the tone detection systems, apparatuses, and methodscould be utilized in connection with other communication systems. TheG.994.1 standard utilizes tones transmitted and received at varyingfrequencies to accomplish a handshake. A handshake may, in turn,communicate transmitting and receiving node capabilities so that thosenodes can exchange or communicate information in a commonly compatibleway.

To accomplish that handshake, signals may be communicated between nodeson a network, such as the network illustrated in FIG. 1. That DSLhandshake may be communicated across an analog public switched telephonenetwork (“PSTN”) by way of tones, represented by sine waves withfrequencies defined by carrier sets. Currently, DSL carrier sets includeA43, B43, C43, and A4 carrier sets. Those carrier sets each have one ormore upstream and downstream carriers. For example, in the A43 carrierset, downstream carriers with carrier indices of 40, 56 and 64 arecurrently used. The frequency of each downstream carrier may be found bymultiplying the downstream carrier by the signalling family frequency ofwhich it is a part. Thus, communication on the A43 carrier set may beperformed at frequencies of 40 times 4.3125 kHz, or 172.5 kHz; 56 times4.3125 kHz, or 241.5 kHz; and 64 times 4.3125 kHz, and 276.0 kHz.Upstream carrier frequencies may be specified in each carrier set. Atleast one other carrier set has been proposed, and it is expected thatembodiments of tone detection provided herein will be applicable toother carrier sets as well.

The A43, B43, and C43 carrier sets are used principally with ADSL indifferent parts of the world, with A43 used primarily in North America,B43 used primarily in Europe, and C43 used primarily in Japan. The A4carrier set is a member of the 4 kHz signalling family that uses asingle upstream carrier and single downstream carrier. The A4 carrierset is used primarily with symmetric DSL modem types.

A carrier set consists of one or more frequencies capable of beingmodified to carry information by, for example, amplitude modulation,frequency modulation, phase modulation, or a combination of two or moreof those forms of modulation. Amplitude is the signal strength, orsignal power, and is the relative “height” of the wave. Frequency is therate at which an electromagnetic waveform alternates as is usuallymeasured in Hertz (cycles per second) and equals the number of completecycles occurring in one second. Phase is the relationship between asignal and its horizontal axis, also called the zero access point. Afull signal cycle describes a 360° arc. Embodiments of the tonedetection techniques may be used with phase modulation, as described inconnection with the G.994.1 standard, or other modulation basedtechniques.

The carrier set in DSL, for example, allows 1 bit stream to be carriedon a multi-tone signal. Carrier set A43, for example, specifies threedownstream frequencies of 40 times 4.3125 kHz, 56 times 4.3125 kHz, and64 times 4.3125 kHz creating a multi-tone signal. Those tones combine toform a multi-tone signal information, typically in the form of bits ofdata, are transmitted by changing some feature of the signal (e.g.,frequency, amplitude or phase of the signal), transmitting the signalsby modulation from the transmitting node, and then changing the signalback by demodulation upon reception at the receiving node. Of course,similar carrier systems allow for multiple information channels to becarried by many other communication systems as well.

Characteristics of a signal transmitted or received are reflected in thesamples corresponding to that signal. To identify or detect the signaltransmitted or received, those samples must be processed. Naturally,processing power is required to process each of those samples of asignal, however. A large number of samples, therefore, require a largeamount of processing power, thereby reducing the amount of processingpower available to perform other functions. Too small of a number ofsamples, however, may cause the loss of signal characteristics, whichmay lead to improper identification of the signal. Thus, the presenttone detection technique determines an optimum number of samples, forexample per symbol, and utilizes that number of samples to optimize tonedetection. That number of samples is also referred to as a window sizeherein.

A signal to be communicated across a network by way of, for example, aPSTN may be generated by a transmitting node and received by a receivingnode in samples. Those samples are typically discrete portions of thesignal that, in combination, form, for example, one or more amplitudesand one or more phase shifts representing one or more data streams ofinformation. The samples are generated at the transmitting node by asample generating device and translated into digital information by atranslating device at the receiving node. Thus, signals may becommunicated by way of samples at both transmitting and receiving nodes.

Embodiments of the tone detection techniques may use two or more windowsizes to determine a small window size that provides effective tonedetection. In those embodiments, a range of window sizes may bepredetermined experimentally to determine a small window size at whichrobust communication is achieved. For example, a block size of 256 or276 samples may be used to accommodate robust communication instead of awindow size of 512, 1024, or greater samples per window. Moreover, theuse of small sample sizes minimizing processing requirementsbeneficially frees processing power that would otherwise be used toprocess a large number of samples so that the signal may be processed intwo of more block sizes. Use of two or more block sizes furthermoreachieves a double or triple or other multiple check of informationcommunicated by way of the signal.

A Fourier transform may be utilized to process tone sample blocks as isknown in the signal processing technologies. The sampling system samplesthe tone carrying signal at discreet intervals. The Fourier transformconverts the sampled signal to a function of frequency. That frequency,in turn, may reveal the signal being carried over a set of frequencies.Thus, multiple tones from, for example, the A43, B43, C43, or A4carriers may be transmitted or identified in the signal utilizing aFourier transform.

The device performing the Fourier transform may be any device programmedor created to perform the Fourier transform. For example, the device maybe a processor such as the DSP. The DSP or another device may seek adetector threshold and determine whether one or more tones are presentin the signal.

A block size of 276 samples per symbol, utilized at 204 has been foundthrough experimentation to provide robust tone detection in the A4carrier and a block size of 256 samples, utilized at 206, has beenthrough experimentation to provide robust tone detection in the A43,B43, and C43 carriers. Thus, manipulation of blocks of 276 samples or256 samples may be desirable. At 208, a Fourier transform, such as theDFT or FFT, processes the sampled signal.

FIG. 4 a is a simulated signal plot 220 for a 276 sample window size andFIG. 4 b is a simulated signal plot 250 for a 256 sample window sizethat illustrate certain advantages of embodiments of the tone detector.The signal illustrated in the simulated signal plots 220 and 250consists of an A4 carrier, A43 carriers and B43 carriers and so includesseven different tones at 20 kHz for the A4 carrier; 172.5 kHz, 241.5kHz, and 276.0 kHz for the A43 carrier; and 310.5 kHz, 379.5 kHz, and414.0 kHz for the B43 carrier.

It may be seen by reference to that FIG. 4 a that the 20 kHz A4 carriertone may be easily detected utilizing the 276 sample window size. Thatmay be seen by reference to the peek at 20 kHz 222 in the 276 samplesignal plot 220. The 241.5 kHz A43 carrier tone 226 and 310.5 kHz 230and 379.5 kHz B43 carrier tones, however, are not detected as wellutilizing that 276 sample window size as they are utilizing a 256 samplewindow, as may be seen in FIG. 4 b. The 379.5 kHz tone does not evenappear in the 276 sample signal plot 220, indicating that tone is not atall well detected utilizing 276 samples per symbol. The 276 samplewindow, however, is excellent for detecting the 20 kHz A4 carrier.

Moreover, the 276 sample window does indicate the presence of tones withfrequencies of 172.5 kHz, 241.5 kHz, and 276.0 kHz for the A43 carrier;and 310.5 kHz and 414.0 kHz for the B43 carrier at various levels. Thus,the 276 sample window may be used to double check the presence of thosetones when used in combination with a 256 sample window. That helps tomaximize the robustness, accuracy and reliability of the window-sizeadaptive tone-detection technique.

It may be seen by reference to that FIG. 4 b that the 172.5 kHz 254,241.5 kHz 256, and 276.0 kHz 258 A43 carrier frequencies and the 310.5kHz 260, 79.5 kHz 262, and 414.0 kHz 264 B43 carrier frequencies aredetected well utilizing a window size of 256 samples. The 20 kHz 252 A4carrier frequency, however, is not detected as well as utilizing the 256sample window size as it was detected utilizing the 276 sample window,as may be seen by the smaller 20 kHz peak 252. The 256 sample windowdoes, however, indicate the presence of a tone with a frequency of 20kHz. Thus, the 256 sample window may be used as a double check fordetecting tones at a 20 kHz frequency when used in combination with the276 sample window size. Thus it may be seen that a double triple orother multiple criteria based window size adaptive technique maximizesthe robustness, accuracy, and reliability of tone detection.

While embodiments of the present tone detection systems, apparatuses,and methods have been described in detail and with reference to specificembodiments thereof, it will be apparent to one skilled in the art thatvarious changes and modifications can be made therein without departingfrom the spirit and scope thereof. For example, embodiments of thepresent tone detection systems, apparatuses, and methods may be appliedto communication mediums other than DSL. Thus, it is intended thatembodiments of the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

1-24. (canceled)
 25. A method, comprising: sampling a received signalover a period to obtain a first sample block having a first quantity ofsamples and a second sample block having a second quantity of samples,the first quantity being different than the second quantity; andprocessing the first and second sample blocks to detect a plurality oftones in the received signal, wherein each of the plurality of toneshave a different frequency.
 26. The method of claim 25, wherein saidprocessing is associated with a small-sized discrete Fourier transform.27. The method of claim 26, wherein said processing is associated with asingle-point discrete Fourier transform.
 28. The method of claim 25,wherein said processing is associated with a fast Fourier transform. 29.The method of claim 25, wherein said processing is associated with atleast one tone detector threshold.
 30. The method of claim 25, whereinthe period is associated with a symbol period.
 31. The method of claim25, wherein the number of samples in the period is pre-determined basedon a communication protocol
 32. The method of claim 25, wherein thesignal is received from one of an analog communication medium and adigital communication medium.
 33. The method of claim 32, wherein thesignal is received from a digital subscriber line.
 34. An apparatus,comprising: a receiving unit to receive a signal; a sampling unit tosample the received signal over a period to obtain a first sample blockhaving a first quantity of samples and a second sample block having asecond quantity of samples, the first quantity being different than thesecond quantity; and a digital signal processor to transform the firstand second sample blocks to detect a plurality of tones in the receivedsignal, wherein each of the plurality of tones have a differentfrequency.
 35. The apparatus of claim 34, wherein the receiving unitincludes an analog front end circuit.
 36. The apparatus of claim 34,wherein transform is associated with at least one of: (i) a small-sizeddiscrete Fourier transform, (ii) a single-point discrete Fouriertransform, or (iii) a fast Fourier transform.
 37. An article ofmanufacture comprising: a computer readable medium having stored thereoninstructions which, when executed by a processor, cause the processorto: sample a received analog signal over a period to obtain a firstsample block having a first quantity of samples and a second sampleblock having a second quantity of samples, the first quantity beingdifferent than the second quantity; transform the first and secondsample blocks using at least one of: (i) a small-sized discrete Fouriertransform, (ii) a single-point discrete Fourier transform, or (iii) afast Fourier transform; and detect plurality of tones based ontransformed information, wherein each of the plurality of tones have adifferent frequency.
 38. The article of claim 37, wherein the period isassociated with a symbol period.
 39. The article of claim 38, whereinthe first quantity of samples is 276 samples and the second quantity ofsamples is 256 samples.
 40. The article of claim 37, wherein the firstand second quantities are large enough that substantially all receivedsymbols are accurately translated into digital information.
 41. Thearticle of claim 37, wherein at least one of the tones is associatedwith an A4, A43, B43, or C43 carrier.
 42. A system, comprising: areceiving unit to receive a digital subscriber line signal; a samplingunit to sample the received signal over a period to obtain a firstsample block having a first quantity of samples and a second sampleblock having a second quantity of samples, the first quantity beingdifferent than the second quantity; a detector to transform the firstand second sample blocks to detect a plurality of tones in the receivedsignal, wherein each of the plurality of tones have a differentfrequency; and a communication adaptor.
 43. The system of claim 42,wherein the digital subscriber line signal is received from a remotedevice and the communication adaptor is to provide informationassociated with the received signal to a local processing system. 44.The system of claim 42, wherein the first and second quantities arelarge enough that substantially all received symbols are accuratelytranslated into digital information.
 45. The system of claim 42, whereinat lease one of the tones are associated with an A4, A43, B43, or C43carrier.